This invention relates to a manually operated tool of a configuration to be received internally of a pipe and pipe flange for holding the flange in axial alignment with respect to the pipe to facilitate the pipe and flange being welded together. Prior art flange aligners employ a one stage principle for expansion and operates to expand simultaneously into contact with the bore of both the flange and the pipe. Accordingly, the expansion member first contacts the smaller diameter bore, whichever it may be, then as the tool is further expanded contact is made with the larger diameter bore. Such an operation makes it difficult to properly position the flange respective to the pipe because the flange and pipe are being simultaneously engaged by the tool. This type of aligner is not at all satisfactory for aligning flanges to pipe ends wherein large differences in the internal bore between the flange and pipe are encountered.
For example, in pressure vessel construction, the pipe is often of a heavier schedule than the pipe flange to be welded thereon, and accordingly, the internal diameter differences preclude the satisfactory use of many prior art flange aligners.
Accordingly, it would be desirable to have made available a flange aligner having a two stage alignment apparatus, one stage for engaging the pipe independently of a second stage for engaging the flange. With such an apparatus, either the flange or the pipe can first be engaged by the appropriate engaging apparatus, and thereafter the flange can be properly oriented respective to the pipe prior to setting the second stage of the apparatus.
Large pipe flanges weigh several hundred pounds and are very difficult to properly bring into axial alignment and orientation with a pipe. Accordingly, should one be able to secure a flange aligner tool first within the pipe, the flange can subsequently be mounted on the second stage apparatus and the weld gap and flange holes easily set and oriented since the tool now supports the heavy flange. This assures accurate and proper alignment of the flange with respect to the pipe end prior to welding. This also makes it possible to accurately choose the optimum gap between the confronting ends of the flange and pipe.
A tool that achieves the above desirable attributes and overcomes the drawbacks of the prior art is the subject of the present invention.